<?php
    define('DB_HOST','localhost');
    define('DB_USER','Alc');
    define('DB_PASS','123456');
    define('DB_Name','review_app');

    // 新建连接
    $conn = new mysqli(DB_HOST,DB_USER,DB_PASS,DB_Name);

    // 检查连接
    if ($conn -> connect_error) {
        # code...
        die("连接失败".$conn -> connect_error);
    }

    // echo "连接成功！"
?>